The Large-Scale Structure From Non-Gaussian Primordial Perturbations

ABSTRACT The late-time effect of primordial non-Gaussianity offers a window into the physics of inflation and the very early Universe. In this work, we study the consequences of a particular class of primordial non-Gaussianity that is fully characterized by initial density fluctuations drawn from a non-Gaussian probability density function, rather than by construction of a particular form for the primordial bispectrum. We numerically generate multiple realizations of cosmological structure and use the late-time matter power spectrum, bispectrum, and trispectrum to determine the effect of these modified initial conditions. We show that the initial non-Gaussianity has only a small imprint on the first three polyspectra, when compared to a standard Gaussian cosmology. Furthermore, some of our models present an interesting scale-dependent deviation from the Gaussian case in the bispectrum and trispectrum, although the signal is at most at the per cent level. The majority of our models are consistent with cosmic microwave background constraints on the trispectrum, while the others are only marginally excluded. Finally, we discuss further possible extensions of our study.